No only one person in your party needs the suit. If going back to turn in the quest - you might as well kill the King as well. Make sure everyone speaks to the little ogre that pops up after his death about the tribute otherwise the ogres will still aggro.

The gauntlet quest is tough - you have to go to DM W and kill the Prince in the library, which isn't the hard part. You must first shut down the five crystals imprisoning the Demon by killing the elementals that guard them. Finally, you have to kill the Demon which is a PAIN. We wiped at least 6 times - thankfully there is a friendly NPC in the library where you can repair equipment. Eventually we killed him (you must kill the eyes he spawns by having one or two in your party designated to do only that). Next you go to the library where the Prince is. Make sure you as the warrior get plenty of aggro on him first as he zips around the room and is hard to catch if you lose aggro. That being said - you will lose aggro when he knocks you half way across the room (he does this every so often) so it is good to have an off tank to try and keep him under control. He is not nearly as bad as the Demon, but still a tough fight. The whole instance takes about 2 hours to complete with no wipes.

There is also a quest near the third crystal pylon - take it - it is basically just killing the Demon and the Prince, which you are doing anyway, and it gives a decent reward.